Seeking a Friend for the End of the World is about the apocalypse, but it's also a surprisingly realistic story about who we become when all our pretentions and future plans are ripped away. It's a genre-defying melancomedy that manages to be good science fiction and a moving romance at the same time. Best of all, it never cheats you with false optimism about the fate of the world.

The movie begins right where a flick like Armageddon ends — except without the bullshit "we rescued the planet by sacrificing Bruce Willis" thing. The Earth is about to be pulverized by a 70-mile-wide meteor, and all efforts by scientists and heroes to stop it have ended in failure. We meet wistful, directionless Dodge (Steve Carell at his finest) as he sits in a car with his wife, listening to the radio announcement that the Earth will be destroyed in three weeks. We assume that somewhere else on the planet, another movie is playing out, where important politicians and survivalists are being ushered to hardened underground shelters and preparing for post-apocalyptic life. But Dodge is an insurance salesman in the suburbs. He has no hope of making it through this calamite. And just as he turns to his wife for solace, she jumps out of their car and runs into the woods — never to be seen again.

Dodge's life heads into a directionless absurdity. He keeps going to work, fielding ever more bizarre calls about insurance policies. And his friends throw a "last supper" party where everybody indulges in mindless transgression — "Hey, we've got heroin!" the hosts gloat. But Dodge doesn't want to smoke, shoot smack, make out with his best friend's wife, or eat a lot of fattening food. He doesn't know what he wants to do.

That's when he meets Penny (Keira Knightly), a longtime neighbor he's barely noticed. She's just broken up with her lame boyfriend, and has decided to sleep on Dodge's fire escape while the boyfriend clears out his stuff. When she starts sobbing uncontrollably, Dodge invites her inside, where she admits that she was "fifteen minutes late for the last plane" that would have taken her to England to meet death with her happy, extended family. There's not much chemistry between Dodge and Penny, but when riots and fire consume their apartment building, they turn out to have something fundamental in common. They are the kind of people who want to rescue others in a crisis — even a stray dog someone has abandoned. And so they get out of the riot by helping each other (and the dog), and go on a surreal road trip into the twilight of the world.

Though they begin their journey by pledging to help each other find a long-lost love (in Dodge's case) and a plane to England (in Penny's case), it soon becomes obvious that their journey together is going to be their last great adventure. Written and directed by Lorena Scafaria, who wrote Nick and Norah's Infinite Playlist, the movie never tries to pretend that Dodge and Penny were always meant for each other, or that their love could have ever bloomed under other circumstances. Their passion is the sort of thing that fuels flings, an emotional attachment that might burn itself out in a few weeks after they got to know each other. But they don't have weeks. They have days.

Apocalypse has robbed Dodge and Penny of their everyday differences, and revealed them unadorned, as two kind-hearted individuals who just want love and comfort. Along their journey, they meet others who want heroin, guns, orgies, and religion — and Seeking a Friend passes no judgment on these people. We pass through their worlds, and this is a major part of what makes the film so weirdly funny. But everybody is just trying to do what they can to celebrate the end of days, or forget that they are happening.

There are a few uneven bits in the film that feel forced, but for the most part it makes for an incredible science fiction/romance thought experiment. What kind of love would you allow yourself to experience if you didn't have to worry about long-term consequences or social conventions? Even though it's about the end of the world, the movie manages to deliver an unabashedly hopeful story about two ordinary people who meet death by making new human connections. You may find yourself weeping a lot during the second half Seeking a Friend, especially if you're a sentimental fool like me. But even if love isn't your thing, you'll be intrigued by the unflinching way this flick reveals that even when we're all about to die, life goes on.